MARINE METROLOGY

The device of pH sensor calibration mainly consists of thermostatic seawater bath, SPRT, Thermometry Bridge and pH CRM. Through comparing the measurement of pH sensor with CRM’s specified value which got in the same temperature, obtain the error of the instrument. And calibration temperature compensation coefficient by testing under different temperature points.

The Calibration of Turbidity Sensor

Turbidity sensor calibration is using Formazine turbidity standard material* to get the error of instrument.
* Note: Formazine is prepared according to ISO7027-1999, and regularly compares with Chinese turbidity CRM, to ensure the accuracy of its magnitude.

Nutrients sensor calibration is using Nutrients CRM to get the error of instrument.

Marine Biochemical Instruments to be calibrated

WETLabs CYCL-P Phosphate Sensor

CRM (Standard Sea Water)

Standard Seawater is reference material of salinity, made of natural seawater, with accurate salinity value. Approved by AQSIQ, NCOSM can produce China Primary Standard Seawater (approved in 2004) and China Serial Standard Seawater (approved in 1989). Through completely reproduced the PSS-78, we established the national primary standard of seawater salinity.

China Primary Standard Seawater is national primary certified reference material (CRM) (GBW 13150), and it has a salinity value of 35 (U=0.001). According to PSS-78, it can trace to KCl standard solution directly, and can be certificated accurately, equivalent to the international level. China Serial Standard Seawater is national secondary CRM [GBW(E) 130011], and it consists of five kind of standard seawater with different salinity value (5, 20, 30, 35, 40 respectively, U=0.003), and can trace to China Primary Standard Seawater.